The Lancet was the first to report the use of anticardiolipin antibody test in a group of patients at risk of recurrent arterial and/or venous thrombosis and recurrent pregnancy losses, 23 years ago. The condition characterized by specific clinical and laboratory signs and initially called the anticardiolipin syndrome came to be known as the antiphospholipid syndrome (APS) when crossreactivity of cardiolipin with other phospholipids was revealed. The study of APS still arouses controversy. Even after two decades of research, there is disagreement on the standardisation and interpretation of antiphospholipid antibody (APLA) test results. More international workshops have been organized on APLA tests than on any other autoantibody test. However, there is still wide interlaboratory variation in APLA detection. Therefore, comprehensive quality control procedures have to be integrated into the routine workload of laboratories performing APLA analysis. Participation in an external quality assessment (EQA) scheme is essential for any laboratory seeking to maintain and provide quality service.

        Key words: antiphospholipid syndrome – antiphospholipid antibodies – standardisation – external quality assessment